JPH06335632A - Molded adsorbing body - Google Patents

Abstract

PURPOSE:To obtain an adsorbing body high in wet and dry strength and excellent in dimensional stability and wet heat resistance by using a binding material in relatively low ratio. CONSTITUTION:In the molded adsorbing body mainly containing active carbon, the active carbon is combined by using a fibrillated aramid fiber as the binding material and entangling the binding material. In this case, fibrillation means to make an unit of fiber (fiber like body) a fine dendritic structure capable of easily entangling. High wet and dry strength are attained by the binding structure due to the entanglement of fibers. The adsorbing material is excellent in dimensional stability and is obtained by using the binding material relatively low ratio. The adsorbing body is suitable for the regeneration by steam treating and is particularly suitable for an adsorbing material for a water purifier because of the excellent wet heat resistance.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a molded adsorbent used for adsorbing and removing coloring substances, odorous components and other harmful substances contained in a gas phase or a liquid phase.

[0002]

2. Description of the Related Art A conventional molded adsorbent (hereinafter simply referred to as "molded body")
(Also referred to as), a structure having a structure in which a heat-melting synthetic resin is used as a binder and the activated carbons are bonded (adhered) to each other by heat-melting the same has been known. And this thing was manufactured as follows. That is, for example, in the case of a molded product containing fibrous activated carbon as a main component, 10 to 25% by weight of a heat-meltable synthetic resin is mixed with the total weight of the molded product to prepare a uniform aqueous slurry. After dipping the mold in the liquid and stacking a certain amount of solid content on the mold surface by suction method and removing from the liquid, dehydration treatment is performed to obtain a wet (wet) shaped product, which is then removed from the mold. By taking out and heating to a predetermined temperature, the binder is heat-melted to bond and dry the activated carbons.

[0003]

However, in the above technique, the shape-retaining strength is extremely low at the stage of the wet shaped body, and when it is gripped by hand, deformation or shape is required unless it is done very carefully. There was a difficulty in handling, such as the collapse. Therefore, there has been a problem that the production efficiency or the yield is poor accordingly. On the other hand, if the ratio of the binder is increased in order to increase the handling strength, the water permeability and the adsorption capacity of the molded adsorbent will be reduced accordingly. Further, since the activated carbons are bonded to each other by heating and melting to a predetermined temperature, a heating and melting step (production facility) is required. In addition, when polyvinyl alcohol (PVA), polyethylene, polypropylene, polyester, etc., which are commonly used as the binder, are used, the shrinkage after drying of the molded product is 10 in any case.
It is as large as -15%, so that there is also a problem that it is not possible to expect high precision of the dimension of the molded adsorbent (product).

Under these circumstances, the inventor of the present application found out the following facts when various samples were manufactured using various materials as the binder for the molded body containing activated carbon as a main component. That is, in the case where an appropriate amount of fibrillated aramid fiber is used as a binder and activated carbon is bonded by the entanglement of the fiber, the wet (wet) strength of the molded article is extremely high, and further, after drying. It was found that the shrinkage also stopped within a few percent, the dimensional stability was extremely high, and the strength after drying (product) was also high. When aramid fibers that were not fibrillated were used as the binder, the strength was low both when wet and when dry, and there was a significant problem in shape retention. The present invention was devised to solve the above-mentioned problems of the prior art based on these findings, and has a high wet strength, a high dry strength, and a molded adsorbent having excellent dimensional stability. The purpose is to obtain a binder with a relatively low ratio.

[0005]

In order to achieve the above object, the present invention provides a molded adsorbent formed by molding activated carbon as a main component, using fibrillated aramid fiber as a binder, The activated carbon is bound by the entanglement of the materials. Here, fibrillation means that the unit (filament) of fibers is made into a fine dendritic structure that is easily entangled. In this case, the fibrillated aramid fiber is preferably 0.5 to 15% by weight based on the total weight of the molded adsorbent except the aramid fiber.

[0006]

According to the present invention, since the aramid fiber as the binding material has activated carbon bonded by the entanglement due to its dendritic structure, the binding force or the shape retention in the wet shaped article is obtained. Its strength is high, and its strength is retained even when it is dried. Therefore, the handling (handling) is good, and the production efficiency can be improved accordingly. Further, since the fibrillated aramid fiber has a function of aggregating substances such as activated carbon in the aqueous slurry, the molded product is homogenized, and therefore, high quality product is expected. Further, since it has a structure in which the fibers are bound together by entanglement, it can be obtained by drying at a relatively low temperature. Therefore, the process (equipment) can be simplified, the manufacturing cost can be reduced, the shrinkage due to drying can be reduced, and a molded product with high dimensional stability can be obtained. Furthermore, since the aramid fiber does not usually heat-melt and has a thermal decomposition starting temperature of 400 ° C. or higher, a molded product excellent in heat resistance can be obtained.

The binding material, that is, the aramid fiber, in the present invention has a strong binding force because it is fibrillated, and therefore the amount used (composition ratio) is higher than that in the case of the conventional bonding by heat melting. The amount can be significantly reduced, and can be set to about 0.5 to 15% by weight with respect to 100% by weight of the total amount of activated carbon and other additives, and the water permeability and adsorption capacity of the molded adsorbent can be improved. Was given.
Moreover, the aramid fiber is different from organic substances such as pulp and hemp, and is excellent in water resistance such that it is unlikely to cause decay and shape loss due to it even when used in water (wet state), and therefore, the present invention, It is particularly suitable as an adsorbent (filter) for a water purifier. Furthermore, the aramid fiber has properties such as extremely high heat resistance and excellent wet heat resistance. Therefore, there is no problem even when regenerating (activating) by applying and passing high temperature steam to the molded body to separate and remove the adsorbate, which is suitable for extending the life of the molded body. Is. Further, since aramid fiber is also excellent in solvent resistance, it is suitable as a molded article for solvent adsorption.

[0008]

EXAMPLES Examples embodying the present invention and manufacturing methods thereof will be described in detail. In the molded adsorbent of this example, the activated carbon is a mixture of granular activated carbon and fibrous activated carbon, and an antibacterial material is added as an additive. The specific content (composition) and blending ratio are as follows. Is like. However,
The shaped adsorbent in this example is for a water purifier and is formed in a hollow cylindrical shape, having an outer diameter of 65 mm and a wall thickness of 15 m.
m, and the length is set to 250 mm. That is, the granular activated carbon is a coconut shell type activated carbon mainly composed of micropores, having a grain size of 0.18 to 0.36 mm and a specific surface area of 1550 m @ 2 / g or more. By the way,
This product has a high ability to adsorb odorous components and the like and is suitable for water purifiers. In addition, the fibrous activated carbon is a coal pitch type in this example, and the fiber thickness is 10 μm to 15 μm.
And having a specific surface area of 1500 m 2 / g or more,
The length is adjusted to about 0.5 mm. This is relatively inexpensive as fibrous activated carbon, has a high adsorption performance (speed), and can adsorb a substance having a molecular diameter smaller than that of granular (powdered) activated carbon. And the antibacterial material is
It is an antibacterial zeolite (powder) in which antibacterial metal ions are added to zeolite. This product is suitable for water purifiers because it has a function of preventing the growth of bacteria in the residual water of the molded product and has high safety. The mixing ratio (weight) of these in this example is set to 45:45:10 (wt%).

On the other hand, the binder in this example, that is, the fibrillated aramid fiber, is
It is a meta type having a developed fine dendritic structure, and the diameter (width) of the particles is distributed in the range of 1 to 200 μm, and the length is adjusted to an average of 1 to 3 mm. However, this amount is set to 5% by weight with respect to the total weight described above (the total weight of the molded body excluding the aramid fiber) in this example.

Thus, the material thus prepared is sequentially poured into water stored in a pulper with stirring to form an aqueous slurry, which is then sent to a slurry concentration adjusting tank to adjust the amount of water, A uniform aqueous slurry having a concentration of 0.5% is prepared, and if necessary, an appropriate additive material (chemical agent) is added and the mixture is sent to a molding tank. In this process, the fibrillated aramid fiber has a function of coagulating the activated carbon and the antibacterial material in the slurry. Then, a predetermined molding die is dipped in the slurry in the molding tank, a predetermined amount of solid content is laminated on the mold surface by a suction (vacuum molding) method, taken out from the liquid, dehydrated, and removed from the mold. Then, a wet shaped body is obtained. The thus obtained wet-shaped molded article in this example has activated carbon bonded by entanglement of fibrillated aramid fibers and retains its shape, so that the handling strength is extremely high and deformation or demolding occurs. There was almost no deformation, and it was extremely easy to handle. By the way, next, this wet shaped body was dried at a predetermined temperature, in this example at 100 ° C., for 3 hours. Thus,
From the state in which the activated carbon was bonded by the entanglement of the aramid fibers, a high-strength dry shaped product, that is, a shaped adsorbent, in which only water was removed by evaporation could be obtained. In this example, the shrinkage during drying was maintained at about 0.5 to 1%.

In this example, the case of heating and drying is illustrated, but the shaped adsorbent in the present invention can also be obtained by natural drying. In this example, since the inexpensive granular (powdered) activated carbon was mixed in an appropriate amount ratio, the cost could be remarkably reduced. As a matter of course, this mixing ratio can be set to an appropriate value. However, when particles are used for the activated carbon, the particle size is 0.1
8 to 0.36 mm (bulk density; 0.1 g / cc to 0.3 g)
/ Cc). This is because when the content is in this range, vacuum molding is possible, the water flow performance is not deteriorated, and a sufficient specific surface area (activated carbon adsorption area) can be maintained.

In the above embodiments, the activated carbon is a mixture of granular activated carbon and fibrous activated carbon. However, in the present invention, the case where granular (powdered) activated carbon or only fibrous activated carbon is used as the activated carbon is also described. Can be converted. It is also possible to use activated carbon in other forms such as flakes. The activated carbon may be appropriately selected and used depending on the application of the molded adsorbent such as petroleum pitch.
By the way, in the case of fibrous activated carbon, the fiber diameter is 2 to
30 μm, fiber length 0.1 to 10 mm, radius 8 to 20
It has pores of about angstrom and has a specific surface area of 150.
It is preferable to use one having a size of 0 to 2500 m @ 2 / g.

Although the fibrillated aramid fibers are of the meta type in the above embodiments, para type fibers may be used as long as they are fibrillated. In addition, regardless of the meta type or the para type, the aramid fiber is preferably sufficiently fibrillated in order to enhance the entanglement property, but in both the meta type and the para type, the fiber is in the fibrillated state. However, the particle diameter (width) is in the range of 1 to 200 μm, and the average length is 0.2 to
A material having a thickness of about 3 mm is preferable from the viewpoint of maintaining the strength of the molded product.

The compounding ratio of the fibrillated aramid fiber is appropriately set depending on the use of the shaped adsorbent, but generally it is based on the total weight of the shaped adsorbent excluding the aramid fiber. , 0.5 to 15% by weight, preferably about 1 to 10% by weight. If it is less than 0.5 to 1% by weight, the adsorption capacity is high and the water resistance is small, but both the wet strength and the dry strength are lowered. Also, 1
If it exceeds 0 to 15% by weight, the strength is increased, but the adsorption capacity is lowered and the water resistance is too large. Incidentally, when used as an adsorbent for a water purifier for purifying and filtering water, about 5% by weight is suitable. However,
In order to reduce the shrinkage due to drying, the compounding ratio should be as small as possible. When the ratio is 10% by weight based on the total weight of the shaped adsorbent excluding the aramid fibers in the above-mentioned examples, it is about 0.7 to 2.0%, and when it is 3% by weight, it is 0. The shrinkage rate was about 1 to 0.6%. Depending on the application of the molded adsorbent, an additive (agent) such as a water resistant agent or an aggregating agent, and further, a fibrous substance (material) for enhancing water-passing performance can be mixed. In addition, in the present invention, in addition to the fibrillated aramid fiber, an appropriate binder may be included. For example, an appropriate amount of fibrillated acrylic fiber can be added.

The molded adsorbent according to the present invention is an adsorbent (filter) for a water purifier used for deodorizing and decolorizing drinking water and removing chlorine components, an adsorbent for an air purifier, a solvent in a chemical factory, etc. It can be applied to various applications such as an adsorbent used for the recovery of The shaped adsorbent is not limited to a cylindrical shape with both ends open, but may have a polygonal cross-section such as a square tube shape, a closed end shape (cup shape), or a flat plate shape. It can be embodied as a shape.

[0016]

EFFECTS OF THE INVENTION As is clear from the above description, the shaped adsorbent according to the present invention is formed by entwining fibrillated aramid fibers with each other by entanglement with activated carbon, and therefore, the shaped adsorbent is wet or dry. The strength of the body can be increased. Therefore, in the past, there was a significant difficulty in handling (workability) such that the shape was apt to be deformed unless it was handled extremely carefully at the time of demolding. Since the occurrence of deformation can be significantly reduced, it is extremely effective in improving workability and productivity. In addition, since it has a structure in which aramid fibers are entangled and joined together without being melted by heat, it can be obtained by drying at room temperature or a relatively low temperature, and the melting step (equipment) can be eliminated. Is expected to improve or reduce cost,
Moreover, since the shrinkage during drying is small, a molded product having high dimensional stability can be obtained. Further, since the binding strength is high and the usage amount (composition ratio) of the binding material can be reduced, it is expected that the water permeability and the adsorption capacity of the molded adsorbent will be improved. Moreover, since the aramid fiber is excellent in heat resistance and wet heat resistance, there is no problem in regeneration by steam treatment, and therefore, the molded product according to the present invention has an extremely long life extension. Further, due to the solvent resistance and chemical resistance of the aramid fiber, the molded product according to the present invention is also suitable for solvent adsorption (recovery).

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI Technical display location B01D 53/04 ZAB A C01B 31/08 Z C02F 1/28 G D01F 6/60 311 Z 7199-3B D21H 13/26 21/14

Claims (2)

[Claims] 1. A molded adsorbent formed by molding activated carbon as a main component, wherein fibrillated aramid fiber is used as a binder, and the activated carbon is bonded by entanglement of the binder. Molded adsorbent. 2. The fibrillated aramid fiber, relative to the total weight of the molded adsorbent except the aramid fiber,
The molded adsorbent according to claim 1, which is 0.5 to 15% by weight.